This non-randomized prospective phase II study was designed to investigate the safety and feasibility of adjuvant intensity-modulated radiotherapy or three-dimensional conformal radiotherapy (IMRT/3DCRT) after radical surgery for pT_2-3 N₀M₀ thoracic esophageal squamous cell carcinoma (TESCC) .

Ninety-six patients were enrolled from 2004 to 2011. The prescribed dose was 50-60 Gy in 1.8-2.0 Gy per fraction (5 days per week) to 95%of the planning target volume (PTV) , encompassing the tumor bed and lymphatic drainage regions at high risk according to the primary tumor location. The survival rate was calculated by Kaplan-Meier method.

The average PTV coverage of the prescribed dose was (94.9±0.7) %. The median bilateral lung V₂₀ was 23.6% (9.8%-29.7%) ; the median stomach V₅₀ was 9.4% (0-39.2%) ; the median heart V₃₀ and V₄₀ were 33.3% (0-67.6%) and 17.1% (0-42.0%) , respectively ; the median maximal dose to the spinal cord was 40.4 Gy (32.9-45.5Gy). The number of samples at 5 years was 35. The 5-year overall survival rate and disease-free survival rate were 74%and 71%, respectively. Grade 3 and 4-5 toxicities occurred in 25 (26%) and 0 patients, respectively. Recurrence and metastasis were seen in 22 (23%) patients, of whom 18 (19%) and 11 (12%) had locoregional recurrence and distant metastasis, respectively.

Adjuvant IMRT/3DCRT for pT_2-3 N₀ M₀ TESCC is tolerable and clinically feasible, and provides excellent local control and favorable survival. Further confirmation in a randomized trial is merited.

Esophageal neoplasms/radiotherapy; Radiotherapy, intensity-modulated; Radiotherapy, three-dimensional conformal; Dosimetry; Prognosis